CN107305756A

CN107305756A - Flexible display device

Info

Publication number: CN107305756A
Application number: CN201710262954.3A
Authority: CN
Inventors: 文星现; 郭炳都; 姜知媛; 金镇�; 金一镇; 金志浩; 文炯朗; 辛善喜; 李光奂; 李珍泳; 赵益晥; 韩在铉; 黃仁澈
Original assignee: Samsung Electronics Co Ltd; Samsung SDI Co Ltd
Current assignee: Samsung Electronics Co Ltd; Samsung SDI Co Ltd
Priority date: 2016-04-22
Filing date: 2017-04-20
Publication date: 2017-10-31
Anticipated expiration: 2037-04-20
Also published as: CN107305756B; US10476037B2; US20170309867A1

Abstract

Disclose a kind of flexible display device.The flexible display device includes display unit, the first adhesive film, optical film, the second adhesive film and the fenestrated membrane stacked gradually by regulation order, wherein the second adhesive film has about 200g/m²24hr or smaller water vapour permeability, and the first adhesive film has the restoring force calculated by equation B lower than the second adhesive film.

Description

Flexible display device

The citation of related application

This application claims the Korean Patent Application No. 10-2016- submitted in Korean Intellectual Property Office on April 22nd, 2016 0049627 and the Korean Patent Application No. 10-2016-0170836 submitted on December 14th, 2016 rights and interests, it is all public Content is opened to be incorporated herein by citation.

Technical field

The present invention relates to flexible display device.

Background technology

Recently, optical display means, such as liquid crystal display, organic light emitting diode display replace glass base using film Plate or high rigidity substrate.Therefore, developing the flexible display device that can be folded and deploy in related technology.

There is flexible display device wherein various optical films and fenestrated membrane (window film) to be stacked on the knot on display unit Structure.Especially, display unit can also be manufactured in the form of a film.Display unit, optical film and fenestrated membrane can pass through OCA (optics Transparent adhesion) film is attached to each other.It is therefore desirable to which OCA films can combine display unit, optical film and fenestrated membrane, and allow flexibility Display device is fully folded, while ensuring good reliability and/or durability.For display device, OCA films are needed with low Yellowness index change (YI), while showing the good transparency.

Can on the direction of display unit or on the direction of fenestrated membrane folded flexible display device.Especially, Neng Gou The flexible display device that the side of display unit is folded up allows many beholders while display is watched, so as to provide good Effectiveness.Accordingly, there exist for flexible display device (even if present dynasty is displayed to when part is folded prevented also from bubble formation or broken Split) the need for.On the other hand, display unit, particularly oled panel, are not only influenceed, Er Qieshou by moisture and/or oxygen External impact influences.Although encapsulant can be coated to oled panel to prevent moisture and/or oxygen from entering oled panel, The problem of still suffering from the thickness increase of flexible display device., can be above oled panel in order to improve OLED impact resistance Or add ons are installed below.However, this can increase the thickness of flexible display device, and it is aobvious to deteriorate the flexibility in use Show the foldability of equipment.

The background technology of the present invention is disclosed in Japanese Unexamined Patent Publication 2007-176542.

The content of the invention

According to an aspect of the present invention, flexible display device include stacked gradually by regulation order display unit, first Adhesive film, optical film, the second adhesive film and fenestrated membrane, the second adhesive film have about 200g/m²24hr or smaller water vapour is saturating Rate (penetrance, transmission rate) is crossed, and as calculated by equation B, the first adhesive film has than the second adhesion The low restoring force of film：

[equation B]

Restoring force=(1- (X₁)/(X₂)) × 100,

Wherein X₁And X₂It is identical with defined in the detailed description of the present invention.

Brief description of the drawings

Fig. 1 is the sectional view of flexible display device according to an embodiment of the invention.

Fig. 2 is the concept map for measuring the sample of peel strength.

Fig. 3 is the sectional view for folding the sample of test.

Fig. 4 is the sectional view and plan for measuring the sample of restoring force.

Fig. 5 is the figure for calculating restoring force.

Embodiment

Embodiments of the present invention are described in detail with reference to the attached drawings, to provide the comprehensive of the present invention to those skilled in the art Understand.It should be appreciated that the present invention can be implemented in a different manner, and the present invention is not limited to implementation below.Attached In figure, for the sake of clarity, the part unrelated with specification will be omitted.Throughout the specification, identical element will be by identical Reference represent.

As used herein, refer to the attached drawing defines the term of space correlation, such as " top " and " bottom ".Therefore, it should manage Solution, " top " can be with " bottom " used interchangeably.It should be appreciated that when layer be referred to as another layer " on " when, it can be formed directly in On another layer, or intermediate layer also may be present.It will thus be appreciated that when layer is referred to as on " directly existing " another layer, Intermediate layer is not inserted between them.

Herein, term " (methyl) acryloyl group " refers to acryloyl group and/or methylacryloyl, and term is " altogether Polymers " can include oligomer, polymer or resin.

Herein, " modulus " of term adhesive film refers to storage modulus (G ').

Herein, term " average grain diameter of organic nanometer granule " refers to use Zetasizer nano-ZS (Malvern Co., Ltd.) measured in water-based solvent or organic solvent, and by the Z average grain diameters of the SEM/TEM nano particles confirmed.

Herein, term " nucleocapsid structure (core-shell structure) " refers to typical nucleocapsid structure.In addition, Each in core and shell can be made up of single or multiple lift, and term " outermost layer " refers to the outermost layer among multiple layers.

Herein, " water vapour permeability " of adhesive film is the value measured according to the water vapour permeabilities of KS A 1013.

Herein, " rate of change of yellowness index " of adhesive film is the value calculated by equation A：

[equation A]

Yellowness index rate of change=| Y2-Y1 |/Y1x 100,

Wherein Y1 is the initial yellowness index of adhesive film, and

Y2 is the yellowness index for making adhesive film be in 60 DEG C and 95% relative humidity (RH) measurement after lower 240 hours.

Herein, " restoring force (restoration force) " can be calculated by equation B：

[equation B]

Restoring force=(1- (X₁)/(X₂)) × 100,

Wherein X₁And X₂Through the following steps that the value obtained：Assuming that the two ends of polyethylene terephthalate (PET) film It is respectively defined as first end and the second end.For calculate the sample of restoring force by by the first PET film via with length × The adhesive film of the size of width (20mm × 20mm) is attached to one another with the second PET film to be prepared so that the first of the first PET film End and the second end of the second PET film are attached each other by the order at the second end of the PET film of first end/adhesive film/second of the first PET film Connect.Fixture is individually fixed in the second end of the first PET film and the first end of the second PET film.One in fixture is in 10Mpa Load in the case of, at 25 DEG C, another fixture is stretched with 300mm/min, until adhesive film have its original depth (X₀, Unit：μm) 1000% length (X₂, unit：μm), i.e. the 10 of the original depth of adhesive film times, and being kept for about 10 seconds, with Afterwards with draw speed same speed (under 300mm/min) recover another fixture with to adhesive film apply 0kPa after obtain Obtain spread length (X₁, unit：μm) adhesive film, in the graph, wherein X-axis is that the spread length and Y-axis of adhesive film are application To the power of adhesive film.

Herein, " bubble formation area ratio " (the bubble generation area ratio) of term display device is Refer to the value (%) determined on the sample of analog display device, the sample is by stacking gradually polyethylene terephthalate (PET) film (thickness：100 μm) it is used as display unit, the first adhesive film (thickness：50 μm), PET film (thickness：50 μm) it is used as light Learn film, the second adhesive film (thickness：50 μm) and PET film (thickness：125 μm) obtained as fenestrated membrane.Specifically, sample is cut Into length x width (160mm × 100mm) size.Sample is bent towards display unit, has about 1cm's to place therebetween Between the parallel framework in gap, and halve the width of sample, and make its aging about 24 hour under 60 DEG C and 93%RH.Pass through Use light microscope (EX-51, Olympus Co., Ltd., magnifying power：30 ×) one of the sample by bubble formation is shot Part obtains image.Image is analyzed by using Mac-View softwares (Mountech Co., Ltd.s), occupied with measuring bubble The gross area and the ratio (%) of the sample gross area be used as bubble formation area ratio.

Below, the flexible display device according to one embodiment of the present invention is described with reference to Fig. 1.Fig. 1 is according to this A kind of sectional view of the flexible display device of embodiment of invention.

With reference to Fig. 1, display unit 91 is included according to the flexible display device 100 of the embodiment, formed in display unit The second adhesion of the first adhesive film 92, the optical film 93 formed on the first adhesive film 92, formation on optical film 93 on 91 The fenestrated membrane 95 of film 94 and formation on the second adhesive film 94.

First adhesive film 92 may be inserted between display unit 91 and optical film 93 display unit 91 being attached to optics Film 93.

First adhesive film 92 can show the restoring force lower than the second adhesive film 94, so that in low temperature or high temperature/humidity Under the conditions of, on the direction of display unit during folded flexible display device, it is allowed to be effectively folded flexible display device.Therefore, Flexible display device 100 can have 0% bubble formation area ratio, such as include the first adhesive film 92 and the second adhesive film 94 Sample on measure, and kept using PET film respectively as display unit, optical film and fenestrated membrane, and after folding.Tool Body, flexible display device 100 can have 0% bubble formation area ratio, and as measured on sample, sample passes through successively The following is stacked to be prepared：Polyethylene terephthalate (PET) film (thickness：100 μm) it is used as display unit, first Adhesive film (thickness：50 μm), PET film (thickness：50 μm) it is used as optical film, the second adhesive film (thickness：50 μm) and PET film (thickness Degree：125 μm) it is used as fenestrated membrane.By sample cut into length x width (160mm × 100mm) size (towards display unit bending, So that the width of sample halves) to place between the parallel framework in the gap with about 1cm in-between, and make it at 60 DEG C and Aging about 24 hours under 93%RH.

The ratio of the restoring force of second adhesive film and the restoring force of the first adhesive film (glue by restoring force/the first of the second adhesive film The restoring force of membrane) 1 can be more than, it is greater than 1 to 1.5 or smaller.Within the range, it is soft when being folded to display unit Property display device can show good folding property.First adhesive film can have the restoring force of the following：About 40% To about 90%, specifically about 60% to about 90%, more specifically about 70% to about 90%, for example, about 40%, about 41%, about 42%th, about 43%, about 44%, about 45%, about 46%, about 47%, about 48%, about 49%, about 50%, about 51%, about 52%, about 53%th, about 54%, about 55%, about 56%, about 57%, about 58%, about 59%, about 60%, about 61%, about 62%, about 63%, about 64%th, about 65%, about 66%, about 67%, about 68%, about 69%, about 70%, about 71%, about 72%, about 73%, about 74%, about 75%th, about 76%, about 77%, about 78%, about 79%, about 80%, about 81%, about 82%, about 83%, about 84%, about 85%, about 86%th, about 87%, about 88%, about 89% or about 90%.Within the range, flexible display device can meet recovery as described above Power ratio, while showing good folding property.

First adhesive film has good impact resistance relative to OLED element, and with lower than the second adhesive film Restoring force, so as to allow towards display unit folded flexible display device.

Second adhesive film 94 is inserted between optical film 93 and fenestrated membrane 95 optical film 93 being attached to fenestrated membrane 95.

Second adhesive film 94 can have the water vapour permeability of the following：About 200g/m²24hr or smaller, specifically Ground about 190g/m²24hr or smaller, for example, about 0g/m²24hr, about 10g/m²24hr, about 20g/m²24hr, about 30g/m²24hr, about 40g/m²24hr, about 50g/m²24hr, about 60g/m²24hr, about 70g/m²24hr, about 80g/ m²24hr, about 90g/m²24hr, about 100g/m²24hr, about 110g/m²24hr, about 120g/m²24hr, about 130g/ m²24hr, about 140g/m²24hr, about 150g/m²24hr, about 160g/m²24hr, about 170g/m²24hr, about 180g/m²24hr, about 190g/m²24hr or about 200g/m²24hr water vapour permeability.Within the range, second glues Membrane can be improved, the life and reliability of the display unit of such as oled panel.Especially, if fenestrated membrane 95 is by with high water vapour The formation such as polyimide film of transmitance, then not only display unit but also optical film, adhesive film etc. may be due to absorbing external water Divide and be damaged.However, the low vapour transmission rate of the second adhesive film 94 means that the second adhesive film prevents outside moisture from entering flexibility Display device, so as to prevent this damage.

Second adhesive film 94 can have the restoring force of about 50% to about 95%.Specifically, the second adhesive film can have The restoring force of the following, e.g., from about 60% to about 95%, more specifically about 70% to about 95%, e.g., from about 50%, about 51%, About 52%, about 53%, about 54%, about 55%, about 56%, about 57%, about 58%, about 59%, about 60%, about 61%, about 62%, About 63%, about 64%, about 65%, about 66%, about 67%, about 68%, about 69%, about 70%, about 71%, about 72%, about 73%, About 74%, about 75%, about 76%, about 77%, about 78%, about 79%, about 80%, about 81%, about 82%, about 83%, about 84%, About 85%, about 86%, about 87%, about 88%, about 89%, about 90%, about 91%, about 92%, about 93%, about 94% or about 95%.Within the range, flexible display device can meet restoring force ratio as described above, while showing good folding property.

First adhesive film 92 needs have the modulus lower than the second adhesive film 94, and in high temperature and/or high humidity Under show good reliability and durability.Therefore, flexible display device 100 is not only at room temperature but also in low temperature or in height Good folding property can be shown under temperature/damp condition, and the bubble under high temperature and/or high humidity can be prevented Generation, rupture and/or layering, so as to provide good reliability and durability under high temperature and/or high humidity.Specifically Ground, at -20 DEG C to 25 DEG C, (modulus of the adhesive film of the modulus of the second adhesive film/first, condition is mutually synthermal to modular ratio The lower modulus for measuring each adhesive film) 1.0 to about 10 or less, specifically 1.01 to about 10, more specifically 1.01 can be more than To about 5, for example, about 1.5, about 2, about 3, about 4, about 5, about 6, about 7, about 8, about 9 or about 10.Within the range, in high temperature/humidity Under the conditions of adhesive film can show good folding property and good reliability and durability, and fenestrated membrane and/or display part Part can be connected fully each other, and also can be folding even if when being provided with form membrane.At 80 DEG C, modular ratio (modulus of the adhesive film 92 of the modulus of the second adhesive film/first, condition is the modulus for measuring each adhesive film at the same temperature) Can be about 1.0 or bigger, specifically about 1.1 to about 5, for example, about 1.1, about 1.5, about 2.0, about 2.5, about 3.0, about 3.5, About 4.0, about 4.5 or about 5.0.

The modulus that can each have at 80 DEG C of first and second adhesive films 92,94 and the modulus (80 at -20 DEG C Modulus at DEG C:Modulus at -20 DEG C) ratio be about 1:1 to about 1:10, specifically about 1:1 to about 1:8, more specifically about 1:1 To about 1:6, e.g., from about 1:1st, about 1:2nd, about 1:3rd, about 1:4th, about 1:5th, about 1:6th, about 1:7th, about 1:8th, about 1:9 or about 1:10. In the range of being somebody's turn to do, under low temperature, room temperature and high temperature, adhesive film can show good folding property, can prevent in wide temperature range The deterioration of adhesiveness in (- 20 DEG C to 80 DEG C) between adhesion, and available for flexible optical element.

The modulus each can with the following at 25 DEG C of first and second adhesive films 92,94：About 15kPa is extremely About 500kPa, specifically about 20kPa to about 300kPa, about e.g., from about 15kPa, about 20kPa, about 25kPa, about 30kPa, 35kPa, About 40kPa, about 45kPa, about 50kPa, about 55kPa, about 60kPa, about 65kPa, about 70kPa, about 75kPa, about 80kPa, about 85kPa, about 90kPa, about 95kPa, about 100kPa, about 110kPa, about 120kPa, about 130kPa, about 140kPa, about 150kPa, About 160kPa, about 170kPa, about 180kPa, about 190kPa, about 200kPa, about 210kPa, about 220kPa, about 230kPa, about 240kPa, about 250kPa, about 260kPa, about 270kPa, about 280kPa, about 290kPa, about 300kPa, about 310kPa, about 320kPa, about 330kPa, about 340kPa, about 350kPa, about 360kPa, about 370kPa, about 380kPa, about 390kPa, about 400kPa, about 410kPa, about 420kPa, about 430, about 440kPa, about 450kPa, about 460kPa, about 470kPa, about 480kPa, About 490kPa or about 500kPa.Within the range, flexible display device can prevent present dynasty's display unit when folding to fenestrated membrane Damage.

The modulus each can with the following at -20 DEG C of first and second adhesive films 92,94：About 20kPa To about 500kPa, specifically about 20kPa to about 400kPa, more specifically about 30kPa to about 300kPa, e.g., from about 20kPa, about 25kPa, about 30kPa, about 35kPa, about 40kPa, about 45kPa, about 50kPa, about 55kPa, about 60kPa, about 65kPa, about 70kPa, about 75kPa, about 80kPa, about 85kPa, about 90kPa, about 95kPa, about 100kPa, about 110kPa, about 120kPa, about 130kPa, about 140kPa, about 150kPa, about 160kPa, about 170kPa, about 180kPa, about 190kPa, about 200kPa, about 210kPa, about 220kPa, about 230kPa, about 240kPa, about 250kPa, about 260kPa, about 270kPa, about 280kPa, about 290kPa, about 300kPa, about 310kPa, about 320kPa, about 330kPa, about 340kPa, about 350kPa, about 360kPa, about 370kPa, about 380kPa, about 390kPa, about 400kPa, about 410kPa, about 420kPa, about 430, about 440kPa, about 450kPa, About 460kPa, about 470kPa, about 480kPa, about 490kPa or about 500kPa.Within the range, regardless of the second adhesive film, Even if flexible display device remains to be folded well at low temperature, and fenestrated membrane and/or display unit can each other fully Connect and also allow even if when being provided with form membrane folding.

The modulus each can with the following at 80 DEG C of first and second adhesive films 92,94：About 10kPa is extremely About 500kPa, specifically about 12kPa to about 300kPa, about e.g., from about 10kPa, about 15kPa, about 20kPa, about 25kPa, 30kPa, About 35kPa, about 40kPa, about 45kPa, about 50kPa, about 55kPa, about 60kPa, about 65kPa, about 70kPa, about 75kPa, about 80kPa, about 85kPa, about 90kPa, about 95kPa, about 100kPa, about 110kPa, about 120kPa, about 130kPa, about 140kPa, about 150kPa, about 160kPa, about 170kPa, about 180kPa, about 190kPa, about 200kPa, about 210kPa, about 220kPa, about 230kPa, about 240kPa, about 250kPa, about 260kPa, about 270kPa, about 280kPa, about 290kPa, about 300kPa, about 310kPa, about 320kPa, about 330kPa, about 340kPa, about 350kPa, about 360kPa, about 370kPa, about 380kPa, about 390kPa, about 400kPa, about 410kPa, about 420kPa, about 430, about 440kPa, about 450kPa, about 460kPa, about 470kPa, About 480kPa, about 490kPa or about 500kPa.Within the range, when flexible display device can prevent the folding of present dynasty display unit pair The damage of fenestrated membrane.

First and second adhesive films 92,94 can each have an about 800gf/in or bigger at 25 DEG C, specifically about 1100gf/in to about 2,500gf/in, about e.g., from about 800gf/in, about 900gf/in, about 1,000gf/in, 1,100gf/in, About 1,200gf/in, about 1,300gf/in, about 1,400gf/in, about 1,500gf/in, about 1,600gf/in, about 1,700gf/ In, about 1,800gf/in, about 1,900gf/in, about 2,000gf/in, about 2,100gf/in, about 2,200gf/in, about 2, 300gf/in, about 2,400gf/in or about 2,500gf/in peel strength.Within the range, the first and second adhesive films can be with Display unit, optical film and fenestrated membrane are attached effectively with each other, so as to improve the reliability of flexible display device.Herein, " peel strength " refers to T- peel strengths.

The rate of change of the yellowness index (YI) each can with about 5% or smaller of first and second adhesive films 92,94, Specifically about 0% to about 1%, e.g., from about 0%, about 1%, about 2%, about 3%, about 4% or about 5%.Within the range, even in Flexible display device is in after high temperature/damp condition for a long time, and flexible display device remains to show good durability.

First and second adhesive films 92,94 can each have about 1 or smaller, specifically about 0.5 or smaller, e.g., from about 0th, the Y1 in about 0.1, about 0.2, about 0.3, about 0.4, about 0.5, about 0.6, about 0.7, about 0.8, about 0.9 or about 1 equation A Value, and about 1 or smaller, specifically about 0.5 or smaller, e.g., from about 0, about 0.1, about 0.2, about 0.3, about 0.4, about 0.5, about 0.6th, the Y2 values in about 0.7, about 0.8, about 0.9 or about 1 equation A.

50 μm of thickness and in visible-range (for example：300nm to 800nm) in, the first and second adhesive films 92,94 Can each have about 3% or smaller, specifically about 2% or smaller, more specifically about 1% or smaller mist degree (turbidity, haze).Within the range, when in the display in use, adhesive film can improve the transparency of display.

First and second adhesive films 92,94 can each have about 1 μm to about 2mm, and specifically about 20 μm to about 1mm, More specifically about 50 μm to about 100 μm of thickness.Within the range, adhesive film can be used for optical display means.

Under 1MHz, the first adhesive film 92 and the second adhesive film 94 can each have the dielectric of about 1.8 to about 3.0 normal Number.Within the range, even if when on the nesa coating being stacked in touch panel, adhesive film remains to make display device without reason The driving of barrier ground.

First and second adhesive films 92,94 can each include adhesive composition (binding compositions, adhesive Composition cured product).Below, describe is used for the first adhesive film according to one embodiment of the present invention With the adhesive composition (hereinafter referred to as " adhesive composition ") of the second adhesive film.

Every kind of adhesive composition for the first and second adhesive films can include (methyl) third for hydroxyl The monomer mixture and initiator of olefin(e) acid copolymer.In adhesive composition, monomer mixture, which can be used as non-polymerised monomer, to be mixed Compound, or can be used as partially polymerized mixture.

Monomer mixture can form (methyl) acrylic copolymer of hydroxyl.(methyl) acrylic acid copolymer of hydroxyl The matrix of thing formation adhesive film, and adhesiveness can be provided for adhesive film.(methyl) acrylic copolymer of hydroxyl can be with With about -150 DEG C to about -13 DEG C, specifically about -100 DEG C to about -20 DEG C, e.g., from about -150 DEG C, about -140 DEG C, about -130 DEG C, About -120 DEG C, about -110 DEG C, about -100 DEG C, about -90 DEG C, about -80 DEG C, about -70 DEG C, about -60 DEG C, about -50 DEG C, about -40 DEG C, About -30 DEG C or about -20 DEG C of glass transition temperature.Within the range, adhesive film can show good in wide temperature range Good folding property and good adhesion strength and reliability.Monomer mixture can include (methyl) propylene of hydroxyl group Acid esters and comonomer." comonomer " is different from (methyl) acrylate of hydroxyl.

(methyl) acrylate of hydroxyl group can include at least one of the following：Containing with least one The C of individual oh group₁To C₂₀(methyl) acrylate of alkyl group, contain the C with least one oh group₅To C₂₀Ring (methyl) acrylate of alkyl and contain the C with least one oh group₆To C₂₀(methyl) acrylic acid of aryl Ester.Specifically, (methyl) acrylate of hydroxyl group can include at least one of the following：(methyl) acrylic acid 2- hydroxyethyls ester, (methyl) acrylic acid 2- hydroxy-propyl esters, (methyl) acrylic acid 3- hydroxy-propyl esters, (methyl) acrylic acid 2- Hydroxybutyl ester, (methyl) acrylic acid 4- hydroxybutyls ester, (methyl) acrylic acid 6- Hydroxyhexyls, single (methyl) acrylic acid 1, 4- cyclohexanedimethanoester esters, (methyl) acrylic acid 1- chlorine-2-hydroxyls propyl diester, single (methyl) acrylic acid binaryglycol ester, single (first Base) acrylic acid 1,6-HD ester, three (methyl) acrylate, pentaerythritols, five (methyl) acrylic acid dipentaerythritol esters, list (methyl) acrylic acid DOPCP, two (methyl) acrylic acid trihydroxy methyl propyl ester, trimethylolethane two (methyl) acrylic acid Ester, (methyl) acrylic acid 2- hydroxyl -3- phenyl epoxides propyl diester, (methyl) acrylic acid 4- hydroxycyclopents base ester, (methyl) propylene At least one of sour 4- hydroxy cyclohexylphenyls base ester and single (methyl) acrylate alkane diformazan alcohol ester, but it is not limited to this.Especially Ground, as (methyl) acrylate of hydroxyl group, contains the C with least one oh group₁To C₅(methyl) of alkyl Acrylate can significantly improve the adhesiveness of adhesive film.

(methyl) acrylic monomers of hydroxyl group can be present in monomer mixture with the amount of the following：About 5% (wt%) to about 40wt%, e.g., from about 10wt% to about 35wt% by weight, e.g., from about 5wt%, about 6wt%, about 7wt%, About 8wt%, about 9wt%, about 10wt%, about 11wt%, about 12wt%, about 13wt%, about 14wt%, about 15wt%, about 16wt%, about 17wt%, about 18wt%, about 19wt%, about 20wt%, about 21wt%, about 22wt%, about 23wt%, about 24wt%, about 25wt%, about 26wt%, about 27wt%, about 28wt%, about 29wt%, about 30wt%, about 31wt%, about 32wt%, about 33wt%, about 34wt%, about 35wt%, about 36wt%, about 37wt%, about 38wt%, about 39wt% or about 40wt%.Within the range, adhesive film has low haze and low moisture-vapor transmission, and can show good adhesion Property.

Comonomer can be comprising (methyl) alkyl acrylate monomer, the monomer containing oxirane, containing expoxy propane Monomer, the monomer of amino-contained, the monomer of amide-containing, the monomer containing alkoxy, the monomer of phosphorous acidic group, containing sulfonic list At least one of monomer of body, the monomer containing phenyl and silane-group containing, but it is not limited to this.

(methyl) alkyl acrylate monomer can include unsubstituted C₁To C₂₀Straight or branched (methyl) alkyl acrylate Base ester.For example, alkyl (methyl) acrylate monomer can include (methyl) methyl acrylate, (methyl) ethyl acrylate, (first Base) propyl acrylate, (methyl) n-butyl acrylate, (methyl) tert-butyl acrylate, (methyl) isobutyl acrylate, (methyl) Amyl acrylate, (methyl) Hexyl 2-propenoate, (methyl) heptylacrylate, (methyl) ethylhexyl acrylate, (methyl) propylene Misery ester, (methyl) Isooctyl acrylate monomer, (methyl) acrylic acid nonyl ester, (methyl) decyl acrylate and (methyl) acrylic acid 12 At least one of Arrcostab.Specifically, C₄To C₈, particularly side chain (methyl) alkyl acrylate is for improving adhesive film Initial adherence intensity.

Monomer containing oxirane is to include ethylene oxide group (- CH₂CH₂O- (methyl) acrylate monomer), and Can include polyethylene oxide alkyl ethers (methyl) acrylate, such as PEO monomethyl ether (methyl) acrylate, PEO list ethylether (methyl) acrylate, PEO list propyl ether (methyl) acrylate, PEO Single-butyl ether (methyl) acrylate, PEO list amyl ether (methyl) acrylate, PEO dimethyl ether (first Base) acrylate, PEO Anaesthetie Ether (methyl) acrylate, PEO monoisopropyl ether (methyl) acrylic acid Ester, PEO list isobutyl ether (methyl) acrylate and PEO list tertbutyl ether (methyl) acrylate, but It is not limited to this.

Monomer containing expoxy propane is to include propylene oxide group (- CH₂CH₂CH₂O- or-CH₂CHCH₃O- (methyl) third) Olefin(e) acid ester monomer, and PPOX alkyl ether (methyl) acrylate, such as PPOX monomethyl ether can be included (methyl) acrylate, PPOX list ethylether (methyl) acrylate, PPOX list propyl ether (methyl) propylene Acid esters, polypropylene oxide monobutyl base ether (methyl) acrylate, PPOX list amyl ether (methyl) acrylate, polycyclic oxygen Propane dimethyl ether (methyl) acrylate, PPOX Anaesthetie Ether (methyl) acrylate, PPOX list isopropyl Base ether (methyl) acrylate, PPOX list isobutyl ether (methyl) acrylate and PPOX list tertbutyl ether (methyl) acrylate, but it is not limited to this.

The monomer of amino-contained can include (methyl) acrylic monomers of amino-contained, such as (methyl) acrylic acid monomethyl ammonia Base ethyl ester, (methyl) acrylic acid list ethylaminoethyl ester, (methyl) acrylic acid mono-methyl amino propyl diester, (methyl) propylene Sour list diethylaminobutyyl ester, (methyl) dimethylaminoethyl acrylate ester, (methyl) acrylic acid diethylamino ethyl ester, (methyl) acrylic acid N- t-butylamino ethyls ester and methacryloxyethyl trimethyl ammonium chloride (methyl) acrylate, But it is not limited to this.

The monomer of amide-containing can include (methyl) acrylic monomers of amide-containing, such as (methyl) acrylamide, N- Methyl (methyl) acrylamide, N- methylols (methyl) acrylamide, N- methoxies (methyl) acrylamide, N, N- methylenes Double (methyl) acrylamides of base and N-2- ethoxys (methyl) acrylamide, but it is not limited to this.

Monomer containing alkoxy base can include (methyl) acrylic monomers containing alkoxy, such as (methyl) acrylic acid 2- methoxy ethyls ester, (methyl) acrylic acid 2- methoxy propyls base ester, (methyl) acrylic acid 2- ethoxy-cs base ester, (methyl) third Olefin(e) acid 2- butoxypropyls ester, (methyl) acrylic acid 2- methoxypentyls ester, (methyl) acrylic acid 2- ethoxypentyls ester, (first Base) acrylic acid 2- butoxy hexyl ester, (methyl) acrylic acid 3- methoxypentyls ester, (methyl) acrylic acid 3- ethoxypentyl esters (methyl) acrylic acid 3- butoxy hexyl esters, but it is not limited to this.

The monomer of phosphorous acidic group can include (methyl) acrylic monomers of phosphorous acidic group, such as 2- (methyl) acryloyl group Epoxide ethyl diphenyl phosphoric acid (methyl) acrylate, three (methyl) acryloyl group epoxide ethyl phosphonic acid (methyl) acrylate and Triacryl epoxide ethyl phosphonic acid (methyl) acrylate, but it is not limited to this.

It can include containing sulfonic acrylic monomers, such as (methyl) acrylic acid sulfonic acid propyl ester containing sulfonic monomer Sodium, (methyl) acrylic acid 2- sulfonic acids sodium and 2- acrylamido -2- methyl-propane sulfonic acid sodium, but it is not limited to this.

Monomer containing phenyl can include (methyl) acrylic monomers containing phenyl, and for example (methyl) acrylic acid is to the tert-butyl group Phenyl ester and the adjacent biphenyl ester of (methyl) acrylic acid, but it is not limited to this.

The monomer of silane-group containing can include the vinyl monomer of silane-group containing, such as (methyl) acrylic acid 2- acetyl group second Acyloxy ethyl ester, vinyltrimethoxy silane, VTES, vinyl three ('beta '-methoxy ethyl) silane, Vinyltriacetylsilane and methylacryloyl epoxide propyl trimethoxy silicane, but it is not limited to this.

Comonomer can be present in monomer mixture with the amount of the following：About 60wt% to about 95wt%, specifically Ground about 65wt% to about 90wt%, about e.g., from about 60wt%, about 61wt%, about 62wt%, about 63wt%, 64wt%, about 65wt%, about 66wt%, about 67wt%, about 68wt%, about 69wt%, about 70wt%, about 71wt%, about 72wt%, about 73wt%, about 74wt%, about 75wt%, about 76wt%, about 77wt%, about 78wt%, about 79wt%, about 80wt%, about 81wt%, about 82wt%, about 83wt%, about 84wt%, about 85wt%, about 86wt%, about 87wt%, about 88wt%, about 89wt%, about 90wt%, about 91wt%, about 92wt%, about 93wt%, about 94wt% or about 95wt%.Within the range, adhere to Film can show good adhesiveness and reliability.

In one embodiment, monomer mixture can include (methyl) acrylate, the copolymerization list of hydroxyl group The homopolymer of body and comonomer has -150 DEG C to 0 DEG C of glass transition temperature.Herein, DSC Q20 (TA can be used Instrument Inc.) measurement relative to each subject monomers homopolymer " glass transition temperature ".Specifically, will be each The homopolymer of individual monomer is heated to about 160 DEG C with about 20 DEG C/min speed, Slow cooling and be maintained in the state of the equilibrium about- 180 DEG C, and be heated to about 160 DEG C to obtain endothermic transition curve with 10 DEG C/min speed.Endothermic transition point of inflexion on a curve quilt It is defined as glass transition temperature.Comonomer, its homopolymer has about -150 DEG C to about 0 DEG C of glass transition temperature, and And can include such comonomer, its homopolymer has about -150 DEG C to about -20 DEG C, more specifically about -150 DEG C to about - 40 DEG C, e.g., from about -150 DEG C, -140 DEG C, -130 DEG C, -120 DEG C, -110 DEG C, -100 DEG C, -90 DEG C, -80 DEG C, -70 DEG C, -60 DEG C, -50 DEG C, -40 DEG C, -30 DEG C, -20 DEG C, the glass transition temperature of -10 DEG C or 0 DEG C.Within the range, adhesive film can be with table Reveal folding property good at low temperature.Comonomer can be included selected from least one of following：For example, (methyl) propylene Acid alkyl ester monomer, including methyl acrylate, ethyl acrylate, isopropyl acrylate, n-butyl acrylate, i-butyl Ester, (methyl) Hexyl 2-propenoate, (methyl) heptylacrylate, 2-EHA, (methyl) dodecylacrylate Deng；(methyl) acrylate monomer containing alkylene oxide, including PEO monomethyl ether (methyl) acrylate, polycyclic oxygen Ethane list ethylether (methyl) acrylate, PEO list propyl ether (methyl) acrylate, PEO monobutyl Ether (methyl) acrylate, PEO list amyl ether (methyl) acrylate, PPOX monomethyl ether (methyl) third Olefin(e) acid ester, PPOX list ethylether (methyl) acrylate, PPOX list propyl ether (methyl) acrylate etc.；Contain (methyl) acrylate monomer of amino, including (methyl) acrylic acid monomethylaminoethylester, (methyl) acrylic acid list ethyl ammonia Base ethyl ester, (methyl) acrylic acid mono-methyl amino propyl ester, (methyl) acrylic acid list ethylamino propyl ester etc.；(first containing alkoxy Base) acrylate monomer, including (methyl) acrylic acid 2- methoxy acrylates, (methyl) acrylic acid 2- methoxyl groups propyl ester, (methyl) Acrylic acid 2- ethyoxyl propyl ester etc.；With (methyl) acrylate monomer of silane-group containing, including (methyl) acrylic acid 2- acetyl group Acetoxyethyl, vinyltrimethoxy silane, VTES etc..

Monomer mixture can further include the monomer of carboxy-containing acid group.The monomer of carboxy-containing acid group can include (first Base) acrylic acid, (methyl) acrylic acid 2- carboxyethyls, (methyl) acrylic acid 3- carboxyls propyl ester, (methyl) acrylic acid 4- carboxyl fourths Ester, itaconic acid, crotonic acid, maleic acid, fumaric acid and maleic anhydride, but not limited to this.Monomer containing carboxylic acid group can be with about 5wt% or less, specifically about 3wt% or less, specifically about 1wt% or less amount are present in monomer mixture.At this In the range of, adhesive film is with the performance in terms of the adhesiveness and reliability further improved.

Monomer mixture may further include (methyl) acrylate containing alicyclic group.(methyl) containing alicyclic group Acrylate is C₅To C₂₀Cycloalkyl (methyl) acrylate monomer and (methyl) isobornyl acrylate, (first can be included Base) acrylic acid norbornene ester and (methyl) cyclohexyl acrylate, but it is not limited to this.It can make individually or with its form of mixtures Use these.(methyl) acrylate containing alicyclic group can about 0.01wt% to about 5wt%, e.g., from about 0.5wt% is to about 3wt%, preferably about 1wt% to about 3wt% amount are present in monomer mixture.Within the range, adhesive film is in heat/moisture Bubble formation or slight lifting are not subjected under test condition, and shows good durability.

Initiator can be with curing monomer mixture, or can solidify (methyl) acrylic acid by its partially polymerized preparation Copolymer.Initiator can be radical photopolymerization initiator or thermal polymerization, itself and (methyl) in hydroxyl group The initiator used in the preparation of acrylic copolymer is identical or different.Photoepolymerizationinitiater initiater can be any initiator, as long as Initiator, during solidifying caused by by light irradiation, can trigger the polymerization of radical polymerizable compound.For example, photopolymerization Initiator can include styrax, acetophenone, hydroxy-ketone, amino ketones, phosphine oxide photoinitiator etc..Specifically, photopolymerization triggers Agent can include styrax, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, styrax n-butyl ether, benzoin isobutyl Ether, acetophenone compound, such as acetophenone, dimethylamino benzoylformaldoxime, 2,2- dimethoxy -2- phenyl acetophenones and 2,2- diethyl Epoxide -2- phenyl acetophenones, 2- hydroxy-2-methyl -1- phenyl-propane -1- ketone, 1- hydroxycyclohexylphenylketones, 2- methyl isophthalic acids - [4- (methyl mercapto) phenyl] -2- morpholinoes-propane -1- ketone, 4- (2- hydroxyl-oxethyls) phenyl -2- (hydroxyl -2- propyl group) ketone, two Benzophenone, to phenyl benzophenone, 4,4'- diethylaminos benzophenone, dichloro benzophenone, 2-methylanthraquinone, 2- ethyls Anthraquinone, 2- tert-butyl groups anthraquinone, 2- amino anthraquinones, 2- methyl thioxanthones, 2- ethyls thioxanthones, CTX, 2,4- dimethyl Thioxanthones, 2,4- diethyl thioxanthones, benzyl dimethyl ketal, acetophenone dimethyl ketal, ESCAROL 507 ester, Oligomeric [2- hydroxy-2-methyls -1- [4- (1- methyl ethylenes) phenyl] acetone] and 2,4,6- trimethylbenzoyls-hexichol Base-phosphine oxide, but not limited to this.These Photoepolymerizationinitiater initiaters can be applied in combination individually or with it.Thermal polymerization can be with Including any initiator, as long as initiator can trigger the polymerization of polymerizable compound.For example, thermal polymerization can include appointing What typical initiator, such as azo, peroxide and redox compound.The example of azo-compound can include 2,2- Azo double (2- methylbutyronitriles), 2,2- trisazo-s double (isobutyronitriles), 2,2- trisazo-s double (2,4- methyl pentane nitriles), 2,2- nitre azoles Double -2- hydroxymethylpropionitriles, dimethyl -2,2- methyl-s double (2 Methylpropionic acid esters) and 2,2-pio azos pair (4- methoxyl groups - 2,4- methyl pentane nitriles), but it is not limited to this.The example of peroxide compound can include：Inorganic peroxide, such as mistake Potassium chlorate, ammonium persulfate and hydrogen peroxide；And organic peroxide, such as diacyl peroxide, peroxy dicarbonate, mistake Oxide ester, peroxidating neodecanoic acid tetramethyl butyl ester, dicetyl peroxydicarbonate double (4- butylcyclohexyls) ester, peroxidating carbonic acid two (2- ethylhexyls) ester, peroxidating neodecanoic acid butyl ester, dipropyl peroxydicarbonate, di-isopropyl peroxydicarbonate, peroxide Change two carbonic acid diethoxy ethyl esters, the own ester of dicetyl peroxydicarbonate diethoxy, the own ester of dicetyl peroxydicarbonate, dicetyl peroxydicarbonate two Methoxybutyl, dicetyl peroxydicarbonate double (3- methoxyl group -3- methoxybutyls) ester, dicetyl peroxydicarbonate dibutyl ester, peroxidating Two carbonic acid two (cetyl) esters, the myristin of dicetyl peroxydicarbonate two, peroxidating neopentanoic acid 1,1,3,3- tetramethyl butyls ester, Peroxidating neopentanoic acid hexyl ester, peroxidating neopentanoic acid butyl ester, peroxidating neopentanoic acid trimethyl acetyl base ester, peroxidating neodecanoic acid Dimethyl hydroxyl butyl ester, peroxidating neodecanoic acid amyl group ester, peroxidating neodecanoic acid butyl ester, the new heptanoic acid ter-butyl ester of peroxidating, Peroxidating neopentanoic acid amyl group ester, peroxy pivalate, peroxidating -2 ethyl hexanoic acid tertiary pentyl ester, lauroyl peroxide Compound, dilauroyl peroxide, two decanol peroxides, benzoyl peroxide and dibenzoyl peroxide, but do not limit In this.The example of redox compound can include the mixture of peroxide compound and reducing agent, but not limited to this.Phase For the monomer mixture of 100 parts by weight, initiator can about 0.0001 parts by weight to about 5 parts by weight, specifically about 0.001 weight Part is measured to about 3 parts by weight, the amount of more specifically about 0.001 parts by weight to about 1 parts by weight is present.Within the range, initiator makes Adhesive composition is fully cured, and can prevent the deterioration of the light transmittance of adhesive film caused by residual initiator.

Adhesive composition can further include crosslinking agent.Crosslinking agent is multi-functional (methyl) acrylate, and can With including for example, difunctional acrylate, such as two (methyl) acrylic acid BDO esters, two (methyl) acrylic acid 1,6- Hexylene glycol ester, two (methyl) propylene neopentyl glycol acid esters, polyethylene glycol two (methyl) acrylate, neopentyl glycol adipic acid two (methyl) acrylate, the ring pentyl ester of two (methyl) acrylic acid two, two (methyl) acrylic acid dicyclopentenyl base esters of caprolactone modification, Ethylene-oxide-modified two (methyl) acrylate, two (methyl) acryloyl-oxyethyl isocyanuric acid esters, two (methyl) propylene Sour allylation cyclohexyl, (methyl) acrylic acid Tricyclodecane Dimethanol ester, two (methyl) acrylic acid dihydroxymethyl bicyclopentanes Ester, the two oxide-modified hexahydrophthalic acid esters of (methyl) acrylic acid epoxy, (methyl) acrylic acid Tricyclodecane Dimethanol ester, two (methyl) acrylic acid neopentyl glycol is modified double [4- (the 2- propylene of trimethyl propyl ester, two (methyl) acrylic acid adamantane esters and 9,9- Oyloxyethoxy) phenyl] fluorine；Trifunctional acrylate, such as three (methyl) acrylic acid trihydroxy methyl propyl diesters, three (methyl) Acrylic acid dipentaerythritol ester, propionic acid are modified dipentaerythritol three (methyl) acrylate, three (methyl) acrylic acid pentaerythrites Ester, epoxy pronane modification trimethylolpropane tris (methyl) acrylate, trifunctional polyurethane (methyl) acrylate and three (first Base) acryloyl-oxyethyl isocyanuric acid ester；Tetrafunctional acrylate, such as (methyl) acrylic acid of diglycerol four and four (methyl) Acrylate, pentaerythritol；Five functional acrylates, such as five (methyl) acrylic acid dipentaerythritol esters；With six functional acrylics Ester, such as six (methyl) acrylic acid dipentaerythritol esters, (methyl) acrylate of dipentaerythritol six of caprolactone modification and poly- Urethane (methyl) acrylate is (for example, the reaction of isocyanate-monomer and trimethylolpropane tris (methyl) acrylate is produced Thing), but it is not limited to this.These crosslinking agents can be used alone or are applied in combination with it.Preferably, crosslinking agent is to contain 2 to 20 Multifunctional (methyl) acrylate of the polyalcohol of individual oh group, to provide good durability.Relative to 100 parts by weight Monomer mixture, crosslinking agent can about 0.001 parts by weight to about 5 parts by weight, specifically about 0.003 parts by weight are to about 3 parts by weight, Specifically the amount of about 0.005 parts by weight to about 1 parts by weight is present.Within the range, adhesive film can show good adhesion Property and reliability.

Adhesive composition can further include silane coupler.Silane coupler is used to cause adhesive film even in height It is maintained in the framework with certain curvature radius after predetermined period of time, still shows good under temperature/damp condition Reliability without bubble or be layered.Silane coupler can be well known by persons skilled in the art typical silane coupled Agent.For example, silane coupler can be included selected from least one of group consisted of：Epoxidation silicon compound, such as 3- Glycidoxypropyltrimewasxysilane, 3- glycidoxypropyls triethoxysilane, 3- glycidoxypropyls third Ylmethyl dimethoxysilane and 2- (3,4- expoxycyclohexyls) ethyl trimethoxy silane；Containing polymerizable unsaturated group Silicon compound, such as vinyltrimethoxy silane, VTES and (methyl) acryloxypropyl front three TMOS；Silicon compound containing amino, such as 3- TSL 8330s, N- (2- amino-ethyls) -3- aminopropyls Trimethoxy silane and N- (2- amino-ethyls) -3- amino propyl methyl dimethoxysilanes；And 3- r-chloropropyl trimethoxyls Silane, but not limited to this.Preferably, silane coupler is epoxidation silane coupler.Monomer relative to 100 parts by weight is mixed Thing, silane coupler can about 0.01 parts by weight to about 3 parts by weight, specifically the amount of about 0.01 parts by weight to about 1 parts by weight deposit .Within the range, under high temperature/damp condition as described above, silane coupler can ensure that adhesive film in the bent state Reliability, and the small peel strength difference that may be provided between low temperature, room temperature and high temperature.

Adhesive composition can further include typical additive, for example curing accelerator, ionic liquid, lithium salts, Inorganic filler, softening agent, molecular weight regulator, antioxidant, age resister, stabilizer, tackifying resin (adhesion- Imparting resin), modified resin (the poly- fourth of polyalcohol, phenol, acrylic acid, polyester, polyolefin, epoxy resin, epoxidation Diene resin etc.), levelling agent, defoamer, plasticizer, dyestuff, pigment (coloring pigment, extender pigment (extender Pigment) etc.), processing aid, UV blocking agents, fluorescent whitening agent, dispersant, heat stabilizer, light stabilizer, UV absorbents, anti- Electrostatic agent, coagulating agent, lubricant, solvent etc..

Each adhesive composition for the first adhesive film and the second adhesive film can also include organic nanometer granule. Preferably, the first adhesive film optionally includes organic nanometer granule, and the second adhesive film includes organic nanometer granule.

Organic nanometer granule shows good viscoplasticity in low temperature and/or at room temperature, and with cross-linked structure, so that Stable viscoplasticity is shown under high temperature/damp condition.In some embodiments, organic nanometer granule can be with hydroxyl base (methyl) acrylic copolymer formation chemical bond of group.Although adhesive composition or adhesive film include organic nanometer granule, Between (methyl) acrylic copolymer of organic nanometer granule and hydroxyl group described below with certain average grain diameter Refringence can ensure that the good transparency.Organic nanometer granule can have following average grain diameter：About 10nm is to about 400nm, specifically about 10nm to about 300nm, more specifically about 10nm to about 200nm, e.g., from about 10nm, about 20nm, about 30nm, About 40nm, about 50nm, about 60nm, about 70nm, about 80nm, about 90nm, about 100nm, about 110nm, about 120nm, about 130nm, about 140nm, about 150nm, about 160nm, about 170nm, about 180nm, about 190nm, about 200nm, about 210nm, about 220nm, about 230nm, about 240nm, about 250nm, about 260nm, about 270nm, about 280nm, about 290nm, about 300nm, about 310nm, about 320nm, about 330nm, about 340nm, about 350nm, about 360nm, about 370nm, about 380nm, about 390nm or about 400nm.In the model In enclosing, organic nanometer granule agglomeration can be prevented, and can ensure that the good transparency of adhesive film.Organic nanometer granule and hydroxyl Refringence between (methyl) acrylic copolymer of group can be about 0.05 or smaller, specifically 0 to 0.03 or smaller, tool Body ground 0 to 0.02 or smaller, e.g., from about 0.01,0.02,0.03,0.04 or 0.05.Within the range, adhesive film can be shown The good transparency.

Organic nanometer granule can have nucleocapsid structure or simple structure, such as pearl type nano particle, but be not limited to This.In one embodiment, organic nanometer granule can have nucleocapsid structure, and its center and shell meet equation 1：

[equation 1]

Tg(c)<Tg (s),

Wherein Tg (c) is the glass transition temperature (unit of core：DEG C), and

Wherein Tg (s) is the glass transition temperature (unit of shell：℃).

Herein, term " shell " refers to the outermost layer of organic nanometer granule.Core can be spheric granules.In some embodiment party In formula, core can be included in the extra play around spheric granules, as long as core has the glass transition temperature for meeting aforesaid equation Degree.

Specifically, core can have the glass transition temperature of the following：About -150 DEG C to about 10 DEG C, specifically about - 150 DEG C to about -5 DEG C, more specifically about -150 DEG C to about -20 DEG C, e.g., from about -150 DEG C, about -140 DEG C, about -130 DEG C, about -120 DEG C, about -110 DEG C, about -100 DEG C, about -90 DEG C, about -80 DEG C, about -70 DEG C, about -60 DEG C, about -50 DEG C, about -40 DEG C, about -30 DEG C, About -20 DEG C, about -10 DEG C, about 0 DEG C or about 10 DEG C.Within the range, adhesive film can show in low temperature and/or good at room temperature Good viscoplasticity.Core can include poly- ((methyl) acrylic acid alkyl each with glass transition temperature within the range Ester), at least one of polybutadiene and polysiloxanes.

Poly- ((methyl) alkyl acrylate) includes at least one of the following：Poly- (methyl acrylate), poly- (propylene Acetoacetic ester), poly- (propyl acrylate), poly- (butyl acrylate), poly- (isopropyl acrylate), poly- (Hexyl 2-propenoate), poly- (methyl Hexyl 2-propenoate), poly- (ethylhexyl acrylate) and poly- (ethylhexyl methacrylate), but not limited to this.

Polysiloxanes can be, such as organosiloxane (co) polymer.Organosiloxane (co) polymer can be with right and wrong Crosslinking or the organosiloxane (co) polymer of crosslinking.The organosiloxane (co) polymer of crosslinking can be used for ensuring impact resistance And coloring.Specifically, the organosiloxane (co) polymer of crosslinking can include dimethyl siloxane, the aminomethyl phenyl of crosslinking Siloxanes, diphenyl siloxane and its mixture.Copolymer with two or more organosiloxanes, nano particle can be with Refractive index with about 1.41 to about 1.50.

The cross-linked state of organosiloxane (co) polymer can be determined based on the solubility in various organic solvents. Strengthen with the degree of cross linking of organosiloxane (co) polymer, the solubility reduction of organosiloxane (co) polymer.For surveying Acetone, toluene etc. can be included by determining the solvent of cross-linked state.Specifically, organosiloxane (co) polymer can have and not dissolve in The part of acetone or toluene.Organosiloxane copolymer can include about 30% or more insoluble matter in toluene.

Organosiloxane (co) polymer can also include alkyl acrylate crosspolymer.Alkyl acrylate cross Polymer can include methyl acrylate, ethyl acrylate, n-butyl acrylate, 2-EHA etc..For example, propylene Acid alkyl ester cross-linked polymer can be n-butyl acrylate or acrylic acid 2- ethyl hexyls with low glass transition temperature Ester.

Specifically, shell can have the glass transition temperature of the following：About 15 DEG C to about 150 DEG C, specifically about 35 DEG C to about 150 DEG C, more specifically about 50 DEG C to about 140 DEG C, e.g., from about 15 DEG C, about 20 DEG C, about 25 DEG C, about 30 DEG C, about 35 DEG C, About 40 DEG C, about 45 DEG C, about 50 DEG C, about 55 DEG C, about 60 DEG C, about 65 DEG C, about 70 DEG C, about 75 DEG C, about 80 DEG C, about 85 DEG C, about 90 DEG C, About 95 DEG C, about 100 DEG C, about 105 DEG C, about 110 DEG C, about 115 DEG C, about 120 DEG C, about 125 DEG C, about 130 DEG C, about 135 DEG C, about 140 DEG C, about 145 DEG C or about 150 DEG C.Within the range, organic nanometer granule can show (methyl) acrylic acid in hydroxyl group Good dispersiveness in copolymer.Shell can include the poly- (methacrylic acid with glass transition temperature within the range Arrcostab).For example, shell can include at least one of the following：Poly- (methyl methacrylate) (PMMA), poly- (methyl Ethyl acrylate), poly- (propyl methacrylate), poly- (butyl methacrylate), poly- (isopropyl methacrylate), poly- (first Base isobutyl acrylate) and it is poly- (cyclohexyl methacrylate), but not limited to this.Preferably, shell includes poly- (methyl methacrylate Ester).

Core or shell can include two layers or more layer, and the outermost layer of organic nanometer granule can include at least one tool Have poly- ((methyl) alkyl acrylate) of about 15 DEG C to about 150 DEG C of glass transition temperature.Specifically, core can be included extremely Few a kind of poly- ((methyl) alkyl acrylate) with about -150 DEG C to about 10 DEG C of glass transition temperature, or can wrap At least one poly- ((methyl) alkyl acrylate) not limited by glass transition temperature is included, as long as whole core has about -150 DEG C to about 10 DEG C of glass transition temperature, but it is not limited to this.In addition, shell, which can include at least one, has about 15 DEG C to about Poly- ((methyl) alkyl acrylate) of 150 DEG C of glass transition temperature, or at least one can be included not by vitrifying Poly- ((methyl) alkyl acrylate) of transition temperature limitation, as long as the vitrifying that whole shell has about 15 DEG C to about 150 DEG C turns Temperature, but it is not limited to this.

Shell can be present in organic nanometer granule with following amount：About 1wt% to about 70wt%, specifically about 5wt% to about 60wt%, about more specifically 10wt% are to about 50wt%, e.g., from about 1wt%, about 5wt%, about 10wt%, about 15wt%, about 20wt%, about 25wt%, about 30wt%, about 35wt%, about 40wt%, about 45wt%, about 50wt%, about 55wt%, about 60wt%, about 65wt% or about 70wt%.Core can be present in organic nanometer granule with following amount： About 30wt% to about 99wt%, specifically about 40wt% to about 95wt%, more specifically about 50wt% to about 90wt%, e.g., from about 30wt%, about 35wt%, about 40wt%, about 45wt%, about 50wt%, about 55wt%, about 60wt%, about 65wt%, about 70wt%, about 75wt%, about 80wt%, about 85wt%, about 90wt%, about 95wt% or about 99wt%.In these of shell and core In content range, adhesive film can keep viscoplasticity in wide temperature range, and show the good adhesive film rate of recovery.

Relative to the monomer mixture of 100 parts by weight, organic nanometer granule can exist with following amount：About 0.5 Parts by weight are to about 15 parts by weight, specifically about 0.5 parts by weight to about 10 parts by weight, more specifically about 0.5 parts by weight to about 8 weight Part, e.g., from about 0.5 parts by weight, about 1 parts by weight, about 1.5 parts by weight, about 2 parts by weight, about 2.5 parts by weight, about 3 parts by weight, about 3.5 parts by weight, about 4 parts by weight, about 4.5 parts by weight, about 5 parts by weight, about 5.5 parts by weight, about 6 parts by weight, about 6.5 parts by weight, About 7 parts by weight, about 7.5 parts by weight, about 8 parts by weight, about 8.5 parts by weight, about 9 parts by weight, about 9.5 parts by weight, about 10 parts by weight, About 10.5 parts by weight, about 11 parts by weight, about 11.5 parts by weight, about 12 parts by weight, about 12.5 parts by weight, about 13 parts by weight, about 13.5 parts by weight, about 14 parts by weight, about 14.5 parts by weight or about 15 parts by weight.Within the range, adhesive film is in viscoplasticity, modulus There is good balance between the rate of recovery.

In one embodiment, in (methyl) acrylic copolymer for preparing hydroxyl group, organic nanometer granule It can be included in the state of polymerizeing with monomer mixture.In this embodiment, organic nanometer granule can be included in containing hydroxyl In (methyl) acrylic copolymer of base group.In another embodiment, adhesive composition can include organic nano Particle, together with (methyl) acrylic copolymer of the hydroxyl group of preparation.In this case, organic nanometer granule can be wrapped It is contained in the adhesive composition separated with (methyl) acrylic copolymer of hydroxyl group.

Adhesive composition can have the viscosity of the about 300cP to about 50,000cP at 25 DEG C.In the range of viscosities, Adhesive composition can have good coating and thickness evenness.

First adhesive film and the second adhesive film can be formed by above-mentioned adhesive composition.In order to be formed at -20 DEG C to 25 DEG C First adhesive film of the lower modulus with the restoring force or higher lower than the second adhesive film, the adhesive combination of the second adhesive film Thing can have, than the adhesive composition for the first adhesive film in monomer mixture, the hydroxyl group of higher amount (methyl) acrylic copolymer (for example, about 1.5 times).Alternately, with the adhesive composition phase for the first adhesive film Than the adhesive composition for the second adhesive film can further include the crosslinking agent or organic nanometer granule (example of higher amount Such as, 10 times).

Next, the preparation method of description adhesive composition.

Can be by the way that initiator be mixed with the monomer mixture of (methyl) acrylic copolymer for hydroxyl group With polymeric monomer intermixture, then to polymerization monomer mixture add initiator and optional organic nanometer granule, crosslinking agent, Silane coupler and various additives prepare adhesive composition.Alternately, (the first for hydroxyl group can be passed through Base) the partially polymerized of monomer mixture of acrylic copolymer prepare prepolymer, then organic nanometer granule added to pre-polymerization Thing prepares adhesive composition.Alternately, can be by the way that organic nanometer granule be added to (methyl) for hydroxyl group The monomer mixture of acrylic copolymer, subsequent section polymerize or polymerize to prepare adhesive composition completely.Polymerization can be wrapped Include polymerisation in solution, suspension polymerisation, photopolymerization, polymerisation in bulk, dispersin polymerization or emulsion polymerization.Specifically, can be at about 50 DEG C to about By in liquid phase initiator, initiator being added into monomer mixture and organic nanometer granule into progress emulsion and gathered at 100 DEG C Close.Initiator can include radical photopolymerization initiator, specifically, radical photopolymerization initiator include it is following at least It is a kind of：Azodiisobutyronitrile, potassium peroxydisulfate, tert-butyl hydroperoxide and diisopropyl benzene hydroperoxides, but be not limited to This.It is partially polymerized to include polymerization with after polymerisation, the about 100cP or higher viscosity at 25 DEG C is specifically being gathered About 1,000cP to about 20,000cP after conjunction.

Next, the forming method of description adhesive film.

It can be reached by the way that adhesive composition is applied on mould release membrance, such as polyethylene terephthalate (PET) film Predetermined thickness, then prepares each of the first and second adhesive films by drying and solidifying.Specifically, adhesive can be combined Thing is applied to the PET film for being subjected to surface treatment.For example, can be by about 250mJ/cm²Or bigger corona pre-treatment is to PET film It is surface-treated, to increase the peel strength of the first adhesive film and the second adhesive film, particularly at about 25 DEG C and about 60 DEG C Peel strength.It can be used, for example corona processor (being now plasma) carries out corona pre-treatment, to handle PET film twice, Plasma is discharged under about 78 dosage simultaneously, but is not limited to this.

Next, description display unit 91.

Display unit 91 is used to drive flexible display device 100, and can include substrate and form the light on substrate Learn element, including OLED (Organic Light Emitting Diode), LED (light emitting diode) or LCD (liquid crystal display)) element.

In one embodiment, display unit can include infrabasal plate, it is thin film transistor (TFT), Organic Light Emitting Diode, flat Smoothization layer (flattenin layer), protective layer and insulating barrier.Infrabasal plate supports display unit, and may be formed to have thin Film transistor and Organic Light Emitting Diode.Infrabasal plate may be alternatively formed to the flexible print circuit for being used to drive touch panel Plate (FPCB).Flexible printed circuit board can be formed further with for driving organic LED array, power supply etc. Timing controller.

Infrabasal plate can include the substrate formed by flexible resin.Specifically, infrabasal plate can include flexible base board, such as silicon Substrate, polyimide substrate, polycarbonate substrate and polyacrylate substrate, but it is not limited to this.

In the viewing area of infrabasal plate, by multiple drives line (not shown) and multiple pickup wires for intersecting each other (not Show) multiple pixel domains are limited, and each pixel domain can form the array with Organic Light Emitting Diode, each of which All include thin film transistor (TFT) and be connected to the Organic Light Emitting Diode of thin film transistor (TFT).In the non-display area of infrabasal plate, to The gate drivers (gate driver) that drives line applies electric signal are formed as the form of grid TIP.Grid is inputted One or both sides of the panel unit formation in viewing area.

Thin film transistor (TFT) crosses the electric current of semiconductor come controlling stream by the electric field applied perpendicular to electric current, and may be formed at On infrabasal plate.Thin film transistor (TFT) can include gate electrode, gate insulator, semiconductor layer, source electrode and drain electrode.Film crystal Pipe can be the following：Using such as indium gallium zinc (IGZO), ZnO or TiO oxide as semiconductor layer oxide Thin film transistor (TFT), using organic material as the OTFT of semiconductor layer, using non-crystalline silicon it is used as semiconductor layer Amorphous silicon film transistor uses polysilicon as the polycrystalline SiTFT of semiconductor layer.

Planarization layer cover film transistor and circuit part, so that the upper surface of thin film transistor (TFT) and circuit part is flat Change so that Organic Light Emitting Diode can be formed on.Planarization layer can be by spin-coating glass (SOG) film, polyimide polymer Or acrylic acid polymer is formed, but it is not limited to this.

Organic Light Emitting Diode is realized by spontaneous emission and shown, and can include the first electricity with regulation order stacking Pole, organic luminous layer and second electrode.Adjacent Organic Light Emitting Diode can be isolated from each other by insulating barrier.Organic light-emitting diodes Pipe can have bottom emissive type structure (light wherein produced from organic luminous layer is launched by infrabasal plate) or top-emission Type structure (wherein the light from organic luminous layer is launched by upper substrate).

Protective layer covers Organic Light Emitting Diode to protect Organic Light Emitting Diode.Protective layer can by inorganic insulating material, Such as SiOx, SiNx, SiC, SiON, SiONC and amorphous carbon (a-C), or organic insulation, such as (methyl) acrylate, The formation such as epoxy polymer, imide polymer.Specifically, protective layer can include wherein inorganic material layer and organic material layer In turn stack one or many encapsulated layers.

Next, description optical film 93.

Optical film 93 can be inserted into the optical element between the first adhesive film 92 and the second adhesive film 94, with to flexibility Display device 100 provides predetermined function.

Although optical film is made up of the individual layer in Fig. 1, optical film can be multiple optical elements with identical function Or the lamination of multiple optical elements with difference in functionality.The structure of the optical film constituted in the lamination by multiple optical elements In, above-mentioned first adhesive film and the second adhesive film, or typical optical clear adhesion (OCA) film can be used.A kind of real Apply in mode, optical film 93 can include at least one of polarization plates and touch panel.Polarization plates can realize interior lights Polarize or prevent the reflection of exterior light to realize display, or the contrast of display can be increased.Polarization plates can be by single Polarizer is constituted.Alternately, polarization plates can include polarizer and form the guarantor on one or two surface of polarizer Cuticula.Alternately, polarization plates can include polarizer and form the protective coating on one or two surface of polarizer. Typical polarizer known in the art, typical diaphragm and typical protective coating can be used as polarizer, protection Film and protective coating.In addition, polarization plates can also include phase shift films (retardation film), compensation film, the film of such as λ/2 and λ/ 4 films and delay liquid coating.When the conductor of human body or such as contact pilotage contacts touch panel, touch panel is by detecting electricity Hold change and produce electric signal, and display unit can be driven by this electric signal.Touch panel passes through patterned flexible conductor Formed, and can include first sensor electrode and second sensor electrode, its each self-forming first sensor electrode it Between and intersect with first sensor electrode.Touch panel can include such as metal nanometer line, conducting polymer and carbon nanometer The conductive material of pipe, but not limited to this.Touch panel can include basal layer and patterned conductor.Basal layer can be by wrapping Include, the insulating synthetic resin of polyethylene terephthalate, polyimides, makrolon, polyacrylate etc. is formed, Or can be polarizer or polaroid protective film to ensure its thin thickness.In the present invention, optical film can include polarization The touch panel of plate and formation in polarization plates.However, in the structure that wherein optical film is polarization plates, touch panel can It is formed directly on display unit 91.

Next, description fenestrated membrane 95.

Fenestrated membrane 95 could be arranged to the outermost layer of flexible display device 100, to protect flexible display device.Fenestrated membrane 95 can be with Including flexible fenestrated membrane.In one embodiment, fenestrated membrane can include basal layer and window coating.

Basal layer is used to support fenestrated membrane, and can be optically transparent optical film.Optical film can in visible-range With with 90% or bigger total light transmittance, and the flexibility by being formed selected from least one of the following can be included Film：Polyester resin, such as polyethylene terephthalate, PEN, polybutylene terephthalate (PBT) and PBN, polycarbonate resin, polyimide resin, polyamide, polystyrene resin, poly- (methyl) Acrylate, including poly- (methyl methacrylate) etc..Adhesive film can have 10 μm to 100 μm, and specifically 20 μm extremely 75 μm, more specifically 30 μm to 50 μm of thickness.Within the range, optical film can be used as the basal layer of fenestrated membrane.

Basal layer can include the film laminated body (laminate film, film laminate) of optical film.Specifically, film layer is folded Body can include the film laminated body of three layers of two or more optical films or more layers, and wherein at least two optical film passes through One is stacked on another by adhesive film.Adhesive film can be by including (methyl) acrylic copolymer for hydroxyl group Monomer mixture and the adhesive composition of organic nanometer granule formed.Adhesive composition can also include initiator, friendship Join at least one of agent, silane coupler and additive.Adhesive film can be identical or different with the first and second adhesive films.

In one embodiment, film laminated body can be wherein the first optical film and the second optical film by adhering to membrane stack Folded trilamellar membrane layered product.First optical film and the second optical film can each include polyethylene terephthalate tree Fat, polycarbonate resin, polyimide resin, poly- (methyl) acrylate, cyclic olefin polymerization resin and acrylic acid tree At least one of fat.First optical film and the second optical film can each have 10 μm to 100 μm, specifically 20 μm to 75 μm, more specifically 30 μm to 50 μm of thickness, and adhesive film can have 10 μm to 100 μm of thickness.Within the range, film Layered product can maximize impact resistance, while keeping the good folding property of flexible display device.First optical film and the second light Identical or different thickness can be had by learning film, and can be formed by identical or different material.Adhesive film can be with first and Two adhesive films are identical or different.

Window coating forms the outermost layer as flexible display device on basal layer, and can become flexible coating. For example, window coating can include the coating formed by silicone resin.In another embodiment, fenestrated membrane can include basis Layer, the window coating formed on the side of basal layer and the hardness enhancing coating formed on the opposite side of basal layer.Window Film 95 can have about 6H or bigger pencil hardness, specifically about 6H to about 9H.

Below, the present invention is more fully described with reference to some embodiments.It should be understood that there is provided these embodiments only For illustrating, without being construed to the limitation present invention in any way.

The preparation of adhesive film

Adhesive film is prepared using following components.

(A) it is used for the monomer for forming (methyl) acrylic copolymer of hydroxyl group

(a1) 2- ethylhexyl acrylates (EHA)

(a2) 4- hydroxybutyl acrylates (HBA)

(a3) 2- hydroxyethylmethacry,ates (HEA)

(a4) acryloyl morpholine (ACMO)

(B) organic nanometer granule

With nucleocapsid structure, average grain diameter is 130nm, refractive index be 1.48 and by emulsion polymerization prepare it is organic Nano particle, its center is formed by poly- (butyl acrylate) (PBA) and is present in 70wt% amount in organic nanometer granule, And shell is formed by poly- (methyl methacrylate) (PMMA) and is present in 30wt% amount in organic nanometer granule

(C) initiator

(c1) Photoepolymerizationinitiater initiater：Irgacure 651(BASF)

(c2) Photoepolymerizationinitiater initiater：Irgacure 184(BASF)

(D) crosslinking agent：1,6 hexanediol diacrylate

Prepare embodiment 1

By being sufficiently mixed the 2- ethylhexyl acrylates (a1) comprising 82wt% of 100 parts by weight in glass container The organic nanometer granule (B) of monomer mixture (A), 4 parts by weight with 18wt% 4- hydroxybutyl acrylates (a2) and The Photoepolymerizationinitiater initiater (c1) of 0.005 parts by weight prepares mixture.After with the dissolved oxygen in nitrogen displacement glass container, make Make mixture progress partially polymerized by UV light irradiations with low-pressure lamp (BL lamps, Sankyo Co., Ltd.s), included so as to prepare Viscosity is (methyl) acrylic copolymer (prepolymer), monomer and the organic nanometer granule of about 2,000cP hydroxyl group Mixture.The other photopolymerization of the amount of 0.3 parts by weight of the monomer mixture (A) relative to 100 parts by weight is added to mixture Initiator (c2), thus prepares adhesive composition.

Adhesive composition is coated on polyester film (mould release membrance, polyethylene terephthalate film, thickness：75μm) On, form the adhesive film that thickness is 50 μm.Using the mould release membrance of 75 μ m-thicks of the upside for being coated on adhesive film, low-pressure lamp is used (BL lamps, Sankyo Co., Ltd.s) is irradiated the both sides of adhesive film about 6 minutes with UV light, so as to obtain transparent pressure-sensitive adhesive sheet.

Prepare embodiment 2 to 6

It is transparent by being prepared with the preparation identical method of embodiment 1 in addition to changing the amount of each component as listed in table 1 Bonding sheet.

The following performance of each adhesive film prepared in embodiment 1 to 6 is prepared is evaluated, and evaluation result is shown in table 1.

(1) modulus：Using rheometer (MCR-501, Anton Paar Co., Ltd.s) under the conditions of automatic response, with 1rad/sec shear rate and 1% strain measurement viscoplasticity.After mould release membrance is removed, the adhesion membrane stack of 50 μ m-thicks is reached To 500 μm of thickness, then using the stamping machine punching press of the 8mm diameters lamination, so as to prepare sample.Mould is measured on sample Amount, while temperature is increased into 90 DEG C from -60 DEG C with 5 DEG C/min, and is recorded under each in -20 DEG C, 25 DEG C and 80 DEG C Storage modulus.

(2) peel strength：Under the plasma discharge of 78 dosage using corona treatment plant will have 150mm × The PET film of the size of 25mm × 75 μm (length × width x thickness) carries out 2 sided corona treatment (accumulated doses：156).By the corona of PET film Surface laminated is handled on two surfaces of the adhesive film that size is 100mm × 25mm × 50 μm (length × width x thickness), is thus made Make sample, shown in such as Fig. 2 (a).By sample hot-pressing processing about 1000 seconds under conditions of about 3.5 bars and about 50 DEG C, and it is fixed on TA.XT_Plus texture analysers (Stable Micro System Co., Ltd.).With reference to Fig. 2 (b), the one of each PET film In the case that TA.XT_Plus texture analysers are fixed in side, surveyed by stretching the opposite side of each PET film with 50mm/min T- peel strengths at 25 DEG C of amount.

(3) yellowness index rate of change：The initial yellowness index (Y1) of adhesive film is determined by transmission beam method.Then, it will glue After membrane is placed 240 hours under 60 DEG C and 95%RH, the yellowness index (Y2) of adhesive film is measured by identical method.According to Equation A, the rate of change of the yellowness index of adhesive film is calculated based on Y1 and Y2.

(4) water vapour permeability：Water vapour permeability is determined according to KS A 1013.

(5) restoring force：By discharging PET mould release membrances in each bonding sheet for being prepared from embodiment and comparing embodiment Obtain adhesive film.Measured at 25 DEG C using TA.XT_Plus texture analysers (Stable Micro System Co., Ltd.) Restoring force.As shown in figure 4, by with length × wide：The adhesive film of 20mm × 20mm size by two PET films (it is long × wide × It is thick：50mm × 20mm × 75 μm) being attached to one another prepares sample so that the two ends of two PET films according to the first PET film/adhesive film/ The order of second PET film is attached to one another long × wide to have between each PET film and adhesive film：20mm × 20mm contact surface Product.Fixture is fixed on to the two ends of the PET film of sample.Herein, by the contact area between the first and second PET films and fixture It is adjusted to long × wide：15mm×20mm.By one of load stationary fixture with 10Mpa, another is stretched under 300mm/min Fixture, until adhesive film has its original depth (X₀, unit：μm) 1000% length (X₂, unit：μm), i.e. adhesive film 10 times of original depth, and kept for about 10 seconds, then with another with draw speed same speed (under 300mm/min) recovery One fixture.After adhesive film to be stretched to 1000% length of its original depth, adhesion when applying 0kPa to adhesive film The spread length of film is defined as X₁.In Fig. 5 figure, X-axis is the spread length of adhesive film, and Y-axis is applied to adhesive film Power.Restoring force is calculated by equation B.

Table 1

Embodiment 1

As shown in figure 3, being made by stacking gradually display unit, the first adhesive film, optical film, the second adhesive film and fenestrated membrane The standby sample for corresponding to flexible display device.

- display unit：First PET film (thickness：100 μm, Cosmoshine TA015, Toyobo)

- the first adhesive film：Adhesive film (the thickness formed by the adhesive composition of preparation embodiment 1：50μm)

- optical film (polarization plates, touch panel)：Second PET film (thickness：50μm)

- the second adhesive film：Adhesive film (the thickness formed by the adhesive composition of preparation embodiment 2：50μm)

- fenestrated membrane：3rd PET film (thickness：125μm)

Embodiment 2 and comparing embodiment 1 to 3

In addition to changing the first adhesive film and the second adhesive film as listed in table 2, prepare in the same manner as example 1 It is respectively corresponding to the sample of flexible display device.

The following performance of the sample prepared in Examples 1 and 2 and comparing embodiment 1 to 3 is evaluated, and evaluation result is shown in Table 2.

(1) test is folded：Each sample prepared in embodiment and comparing embodiment is cut into 100cm × 160cm (long × it is wide) size with prepare for fold test sample, then by it under 50 DEG C and 3.6 bars hot-pressing processing 1000 seconds.Such as Shown in Fig. 3, by sample with towards the state that display unit is bent be fixed on folding tester (CFT series, COVOTEC Co., Ltd) width of sample is halved, and then carries out 100,000 at 25 DEG C with the bending speed of 30 times per minute circulations Secondary bend cycles cause the bent portion of sample have 3mm radius of curvature (1 time circulation refer to by adhesive film fold half once And deploy the operation of adhesive film).After 100,000 bend cycles, the evaluating sample that will suffer from layering or bubble formation is ×, it is zero by the evaluating sample without layering or bubble formation.

(2) by the damage of the caused oled panel of impact：Will in the first PET film by removing corresponding to display unit Oled panel is attached to after each sample prepared in embodiment and comparing embodiment, and oled panel is evaluated by falling ball method Damage.Specifically, after 5cm height is dropped on oled panel, electric power is being applied into oled panel for 30g steel ball. The normal operating of oled panel is evaluated as OK, and the abnormal operation of oled panel is evaluated as NG.

(3) damage of the oled panel caused by moisture：The first PET film of display unit is being corresponded to by removing, will Oled panel is attached to after each sample prepared in embodiment and comparing embodiment, and sample is transferred at 60 DEG C and 93%RH Put 24 hours, and apply electric power to oled panel.The normal operating of oled panel is evaluated as OK, and by the exception of oled panel Operation evaluation is NG.

(4) bubble formation area ratio：By each sample cut growth prepared in embodiment and comparing embodiment × wide： 160mm × 100mm size, towards display unit bending so that sample is placed on the parallel frame in the gap with about 1cm therebetween Between frame, and the width of sample is halved, and make its aging about 24 hour under 60 DEG C and 93%RH, then using Mac-View Software (Mountech Co., Ltd.s) is analyzed by using light microscope (EX-51, Olympus Co., Ltd., magnifying power： 30 ×) image obtained by a part for the sample of bubble formation is shot, to measure the gross area and sample surface that bubble is occupied Long-pending ratio (%) is used as bubble formation area ratio.

Table 2

As shown in table 2, the flexible display device of embodiment still shows good folding when being folded towards display unit Folded property, and the damage of the oled panel caused by impacting with moisture can be prevented.

Therefore, the invention provides a kind of flexible display device, when its display unit of present dynasty is folded, in low temperature to high temperature And/or there is good folding property under high humidity.The invention provides a kind of flexible display device, it can pass through moisture And/or oxygen prevents display unit, the damage of such as oled panel, while improving the impact resistance of oled panel.The present invention There is provided a kind of flexible display device, it includes the adhesive film with low yellowing rate of change, with high temperature and/or high humidity Lower offer high reliability.The invention provides a kind of flexible display device, it can prevent gas under high temperature and/or high humidity Bubble generation, rupture and/or layering, and can be by ensuring adhesiveness good between display unit, optical film and fenestrated membrane come really Protect good reliability and durability.

Although this document describes some embodiments, it is to be understood that, these embodiments are only provided by way of illustration, And under the premise without departing from the spirit and scope of the present invention, those skilled in the art can various modification can be adapted, changes, change And equivalent embodiments.Therefore, the scope of the present invention should not be limited only by appended claims and its equivalent.

Claims

1. a kind of flexible display device, including：Display unit, the first adhesive film, the optics stacked gradually by order as described below Film, the second adhesive film and fenestrated membrane,

Second adhesive film has 200g/m²24hr or smaller moisture-vapor transmission, and

First adhesive film has the restoring force calculated by equation B lower than second adhesive film：

[equation B]

Restoring force=(1- (X₁)/(X₂)) × 100,

Wherein X₁And X₂Through the following steps that the value obtained：Assuming that the two ends of polyethylene terephthalate film are defined respectively For first end and the second end, wherein for calculating the sample of restoring force by by the first polyethylene terephthalate film and Two polyethylene terephthalate films via with length x width for 20mm × 20mm sizes adhesive film be attached to one another into Prepared by row so that the first end of first polyethylene terephthalate film and second polyethylene terephthalate Second end of ester film by the first polyethylene terephthalate film the poly terephthalic acid second two of first end/adhesive film/second The order at the second end of alcohol ester film is attached to one another, and wherein fixture is individually secured to first polyethylene terephthalate film The second end and second polyethylene terephthalate film first end, wherein one in the fixture is with 10Mpa Load fix, another fixture is stretched at 25 DEG C and with 300mm/min, until the adhesive film has X₀μm initial thickness 1000% X of degree₂μm length and kept for 10 seconds, then to recover another fixture with draw speed same speed To obtain X after 0kPa is applied to the adhesive film₁μm spread length the adhesive film, in figure, wherein X-axis is institute The spread length and Y-axis of adhesive film is stated to apply to the power of the adhesive film.

2. flexible display device according to claim 1, wherein the flexible display device has what is measured on sample 0% bubble formation area ratio, the sample is by stacking gradually the poly terephthalic acids of 100 μ m thicks as display unit Glycol ester film, the first adhesive film of 50 μ m thicks, as optical film 50 μ m thicks polyethylene terephthalate film, The polyethylene terephthalate film of second adhesive film of 50 μ m thicks and 125 μ m thicks as fenestrated membrane, and cut into It is long × wide：160mm × 100mm size is obtained, and by sample at 60 DEG C with after aging under 93%RH 24 hours, measurement bubble is produced Area ratio, wherein the sample is bent towards the display unit so that the sample is placed on the gap with 1cm therebetween Between parallel framework, and the width of the sample halves.

3. flexible display device according to claim 1, wherein first adhesive film has than institute at -20 DEG C to 25 DEG C State the lower modulus of the second adhesive film.

4. flexible display device according to claim 1, wherein the restoring force of second adhesive film is glued with described first The ratio of the restoring force of membrane is more than 1 to 1.5.

5. flexible display device according to claim 1, wherein first adhesive film has 40% to 90% recovery Power.

6. flexible display device according to claim 1, wherein second adhesive film has 50% to 95% recovery Power.

7. flexible display device according to claim 1, wherein in first adhesive film and second adhesive film The modulus at 80 DEG C each having:The ratio of modulus at -20 DEG C is 1:1 to 1:10.

8. flexible display device according to claim 1, wherein first adhesive film and second adhesive film is every It is individual with the 5% or smaller yellowness index rate of change calculated by equation A：

[equation A]

Yellowness index rate of change=| Y2-Y1 |/Y1x100,

Wherein Y1 is the initial yellowness index of the adhesive film, and

Y2 is that the yellowing for making the adhesive film be in the adhesive film that 60 DEG C and 95% relative humidity are measured after lower 240 hours refers to Number.

9. flexible display device according to claim 1, wherein the optical film is included in polarization plates and touch panel At least one.

10. flexible display device according to claim 1, wherein the optical film is polarization plates, and further comprises It is formed directly into the touch panel on the display unit.

11. flexible display device according to claim 1, wherein first adhesive film and second adhesive film is every The individual peel strength with the 800gf/in or higher at 25 DEG C.

12. flexible display device according to claim 1, wherein first adhesive film and second adhesive film is every The individual cured product for including adhesive composition, described adhesive composition is included：(methyl) acrylic acid of hydroxyl group is common The monomer mixture of polymers；And initiator.

13. flexible display device according to claim 12, wherein the described adhesive group for second adhesive film Compound further includes machine nano particle, and the organic nanometer granule has 10nm to 400nm average grain diameter.

14. flexible display device according to claim 13, wherein the organic nanometer granule has nucleocapsid structure, institute Stating core and the shell has the glass transition temperature for meeting equation 1：

[equation 1]

Tg(c)<Tg (s),

Wherein Tg (c) be unit for DEG C the core glass transition temperature and

Tg (s) be unit for DEG C the shell glass transition temperature.

15. flexible display device according to claim 13, wherein relative to the monomer mixture of 100 parts by weight, The organic nanometer granule exists with the amount of 0.5 parts by weight to 15 parts by weight.

16. flexible display device according to claim 12, wherein the monomer mixture includes 60wt% to 95wt% (methyl) alkyl acrylate and 5wt% to 40wt% hydroxyl group (methyl) acrylate.

17. flexible display device according to claim 12, wherein described adhesive composition further include initiator At least one of with crosslinking agent.

18. flexible display device according to claim 1, wherein the fenestrated membrane includes trilamellar membrane layered product, the trilamellar membrane Layered product is comprising the first optical film, the second optical film and is inserted in viscous between first optical film and second optical film Membrane.

19. flexible display device according to claim 18, wherein first optical film and second optical film Each formed by least one of the following：Polyester resin, polycarbonate resin, polyimide resin, poly- (methyl) third Alkene acid ester resin, cyclic olefin polymerization resin and acrylic resin.

20. flexible display device according to claim 18, wherein first optical film and second optical film Each there is 10 μm to 100 μm of thickness, and the adhesive film has 10 μm to 100 μm of thickness.

21. flexible display device according to claim 18, wherein the adhesive film is formed by adhesive composition, it is described Adhesive composition includes the monomer mixture and organic nanometer granule of (methyl) acrylic copolymer for hydroxyl group.

22. flexible display device according to claim 18, wherein the adhesive film is first adhesive film or described Second adhesive film.